Rotationally slipping rubber bushing with axial retention feature

ABSTRACT

A bushing is provided having an outer rigid portion and an inner rigid portion concentrically arranged around each other, the inner rigid portion being the innermost component, a flexible portion positioned between the inner rigid portion and the outer rigid portion, the flexible portion configured to space apart the outer rigid portion and the inner rigid portion and each of the outer rigid portion, the inner rigid portion and the flexible portion includes a tapered end configured to connect with a fastener.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present Utility patent application claims priority benefit of theU.S. provisional application for patent Ser. No. 62/109,293, filed onJan. 29, 2015, under 35 U.S.C. 119(e).

FIELD OF THE INVENTION

The present invention relates generally to bushings. More particularly,the present invention relates to a bushing adapted for use in leafspring eyes.

BACKGROUND OF THE INVENTION

Current rubber bushings typically used in leaf springs are made of arubber over molded inner metal and an outer metal. The assembly is pressfit into the outer metal and then the outer metal is roll crimped inwardat its distal ends. The bushing is then press fit into its location inthe vehicle (typically a leaf spring eye) where it is rigidly connectedto the rest of the vehicle via a bolt and a nut. Movement of the vehiclecauses relative motion between the molded assembly (the rubber bonded tothe inner metal) and the outer metal. For proper vehicle performance,the bushing must accommodate the loads in its radial and longitudinal oraxial directions as well as rotation about its longitudinal axis, hereinreferred to as the torsional direction. Current bushings of the priorart can handle radial and torsional loads sufficiently, but lack anadequate axial retention feature. A longitudinal load can cause therubber to deform around the outer metal's crimp and allow the moldedassembly to become dislodged at relatively low loads (less than 5 kN).

The assembly of the prior art as illustrated typically includes anelongated and an inner metal portion. The inner metal portion includesan over molded rubber positioned between the inner metal and the outermetal. The outer metal is crimped at each of its distal ends. Thisconfiguration causes the rubber to deform around the outer metal andallows the assembly to become dislodged.

Accordingly, there exists a need in the art to overcome this deficiencywhile achieving the ideal rotational compliance. While achieving theideal rotational compliance of zero has proven to require a more complexconcept, there exists a need in the art to provide axial retention. Alack of axial retention forces manufacturers to design the bushings forhigher rotational compliances which result in poor vehicle performance.

SUMMARY

In one embodiment, a bushing is provided having an outer rigid portionand an inner rigid portion concentrically arranged around each other,the inner rigid portion being the innermost component, a flexibleportion positioned between the inner rigid portion and the outer rigidportion, the flexible portion configured to space apart the outer rigidportion and the inner rigid portion and each of the outer rigid portion,the inner rigid portion and the flexible portion includes a tapered endconfigured to connect with a fastener.

The flexible portion may be a bonded rubber where the bonded rubberbonded to at least one of the outer rigid portion or the inner rigidportion. The bonded rubber of the flexible portion may include atextured outer surface where the textured outer surface positionedadjacent to an inner surface of the outer rigid component. An outersurface of the flexible portion includes a plurality of ridgespositioned adjacent to an inner surface of the outer rigid component.The outer metal portion includes a main cylindrical section extending totapered end. The rigid inner portion and the rigid outer portion aremade from a material selected from the following: metal, plastic and/orpolymer.

In one embodiment, the flexible portion is a rubber, the outer rigidportion is metal and the inner rigid portion is metal where the rubberof the flexible portion is bonded to at least one of the outer rigidportion and the inner rigid portion. The outer rigid portion isconcentrically arranged around the flexible portion, the flexibleportion is concentrically arranged around the inner rigid portionwherein each of the outer rigid portion, the flexible portion and theinner rigid portion include a central bore, the inner rigid portionconfigured to receive the fastener.

In another embodiment, a bushing assembly is provided having a firstcomponent and a second component. The first component has a first outermetal portion, a first inner metal portion and a first rubber portionconcentrically arranged around each other, the first rubber portionspacing apart the first outer metal portion from the first inner metalportion. At least one of the first outer metal portion, the first innermetal portion and the first rubber portion having a first tapered end.The second component has a second outer metal portion, a second innermetal portion and a second rubber portion concentrically arranged aroundeach other, the second rubber portion spacing apart the second outermetal portion from the second inner metal portion. At least one of thesecond outer metal portion, the second inner metal portion and thesecond rubber portion having a second tapered end. A fastener configuredto connect the first tapered end of the first component and the secondtapered end of the second component, the first component and the secondcomponent configured to at least partially overlap wherein the bushingassembly forms a bottleneck shaped center portion when fully assembled.

The first and second outer metal portions are concentrically arrangedaround the respective first and second rubber portions. Further, thefirst and second rubber portions are concentrically arranged around therespective first and second inner metal portion. The first and secondinner metal portions are configured to receive the fastener.

In one embodiment, a rubber of the first rubber portion is bonded to atleast one of the first outer metal portion or the first inner metalportion. Further, a rubber of the second rubber portion is bonded to atleast one of the second outer metal portion or the second inner metalportion. The bonded rubber of the rubber portion includes a texturedouter surface, the textured outer surface positioned adjacent to aninner surface of the outer metal component. In another embodiment, anouter surface of the rubber portion includes a plurality of ridges wherethe plurality of ridges positioned adjacent to an inner surface of theouter metal component.

In another embodiment, a leaf spring assembly includes a leaf springhaving an eye positioned at a free end, the eye configured to hold abushing. The bushing having a first component connected to a secondcomponent. The first component having a first outer metal portion, afirst inner metal portion and a first rubber portion concentricallyarranged around each other, the first rubber portion spacing apart thefirst outer metal portion from the first inner metal portion. At leastone of the first outer metal portion, the first inner metal portion andthe first rubber portion having a first tapered end. The secondcomponent having a second outer metal portion, a second inner metalportion and a second rubber portion concentrically arranged around eachother, the second rubber portion spacing apart the second outer metalportion from the second inner metal portion. At least one of the secondouter metal portion, the second inner metal portion and the secondrubber portion having a second tapered end. A fastener is providedconfigured to connect the first tapered end of the first component andthe second tapered end of the second component, the first component andthe second component configured to at least partially overlap whereinthe bushing assembly forms a bottleneck shaped center portion when fullyassembled

These and additional features provided by the embodiments describedherein will be more fully understood in view of the following detaileddescription, in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments set forth in the drawings are illustrative and exemplaryin nature and not intended to limit the subject matter defined by theclaims. The following detailed description of the illustrativeembodiments can be understood when read in conjunction with thefollowing drawings, where like structure is indicated with likereference numerals and in which

FIG. 1A illustrates a side view of the assembled bushing of the presentinvention;

FIG. 1B illustrates a reverse configuration of the assembly bushing inaccordance with one or more embodiments shown and described herein;

FIG. 2A illustrates an environmental view of the bushing of the presentinvention used in a leaf spring assembly;

FIG. 2B illustrates an exploded perspective view of the bushing and leafspring assembly;

FIG. 3 illustrates a cross-sectional view of the inner metal componentof the bushing of the present invention;

FIG. 4 illustrates a top view of the inner metal component of thebushing of the present invention;

FIG. 5 illustrates a cross-sectional view of the inner metal componentof the bushing of the present invention;

FIG. 6 illustrates a perspective view of the inner metal component ofthe bushing of the present invention;

FIG. 7 illustrates a cross-sectional view of the outer metal componentof the bushing of the present invention;

FIG. 8 illustrates a perspective view of the outer metal component ofthe present invention;

FIG. 9 illustrates a top view of the molded assembly including the innermetal having the molded rubber on the exterior of the inner metal;

FIG. 10 illustrates a side view of the molded assembly;

FIG. 11 illustrates an alternative cross-sectional view of the moldedassembly along the line A-A as shown in FIG. 9;

FIG. 12 illustrates a cross-sectional view of the molded assembly;

FIG. 13 illustrates a perspective view of the molded assembly of thebushing of the present invention;

FIG. 14 illustrates a top view of the final bushing assembly;

FIG. 15 illustrates a side view of the final bushing assembly;

FIG. 16 illustrates a cross-sectional view along the line A-A of thefinal bushing assembly; and

FIG. 17 illustrates a perspective view of the final bushing assembly.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides for a bushing for improved longitudinalrotational compliance, axial retention, and near rigid characteristicsin all other directions. The bushing includes an outer metal portion, aninner metal portion, and a bonded rubber positioned between the innermetal portion and the outer metal portion. The inner and outer metalportions have bottleneck features adapted to overlap.

The assembly of the present invention provides for a multi assemblybushing having a bottleneck feature in the center of the bushing. Thebushing 100 includes outer metal components 102, 104 having outersurfaces 106, 108. The bushing assembly 100 further includes inner metalcomponents 120, 121 positioned to overlap with the outer metalcomponents 102, 104. A molded rubber 132 is positioned between the innermetal components 120, 121 and the outer metal components 102, 104. Thisassembly utilizes mechanical locking by overlapping the metal components102, 104 and 120, 121. Both the inner metal components 120, 121 and theouter metal components 102, 104 have a bottleneck feature 110, 112, 130,131 to create an overlap when the over molded inner metal 120, 121 ispressed into the outer can of the leaf spring assembly, such asillustrated in FIG. 5A and 5B. A single bushing of the prior art isreplaced by two bottleneck bushings 100 a, 100 b facing opposite waysand occupying the same general space within the can of the leaf springassembly. The leaf spring assembly 200 includes a main leaf springportion along with the eye 204 of the leaf spring. The bushing 100 a,100 b are inserted into the eye 204 and connected together at the innerportions of the bushings 100 a, 100 b. A fastener (or multiplefasteners) 116 are inserted into the center bore 114 of the bushing tosecure the bushings. For either a positive or negative axial loading,the mechanical interlock from one of the halves retains the bushingassembly. This feature also allows for minimal compression of therubber, thus increasing rotational compliance.

The inner metal components 120, 121 are illustrated in FIGS. 6-9. Theinner metal component 120 includes a center bore 114 extending throughthe entire length of the inner metal 120. The inner metal 120 includes afirst portion 124 and a bottlenecked portion 112. The first portion 124is larger in diameter as compared to the bottlenecked portion 112. Asillustrated in FIGS. 6 and 8, the bottlenecked portion is gradual thuschanging the diameter from the first portion 124 to the bottleneckedportion 112 at an angle as illustrated by reference numeral 140. In thefinal assembly, two inner metal portions 120, 121 are provided.

The outer metal portions 102, 104 are larger in diameter as compared tothe inner metal 120, 121. The outer metal portion 104 includes a largecenter portion 126 adapted to receive the inner metal 120, 121. Thecenter portion 126 is generally cylindrical having a smooth interiorsurface. The outer metal 104 includes an outer surface 108 (the outermetal portion 102 having an outer surface 106) which is also generallysmooth. A bottleneck feature 130, 131 is illustrated as tapering downfrom the larger portion 104 a to lower diameter portion 104 b, which isthe bottleneck feature. This taper is illustrated at reference numeral128.

In the present embodiment, the outer metal is SAE J1392 XLF340 steel,but could be any grade of stamping steel or aluminum. Further in thispresent embodiment, the inner metal is ASTM 1040 steel, but could be anymaterial that meets the clamp load requirements and does not providenoticeable creep. Any of the rubber components of the present inventioncould be replaced with plastic, polymer, plastic-like or polymer-likematerials. In the present embodiment, the bonded rubber has a durometerranging from 40-80 ShoreA. In this specific bonder rubber component, thedurometer ranger between 60-75 ShoreA.

Rubber is molded into a thin layer over and bonded to the inner metal120, 121. The rubber 132 includes a plurality of ridges 134 adapted topress against the inner surface of the outer metal. In alternativeembodiments, the rubber 132 is smooth or has various other differenttextures to accommodate the assembly. The molded assembly having therubber 132 molded to the inner metal portion 120 is illustrated in FIGS.12-16. This molded assembly as illustrated in FIGS. 12-16 is press fitinto the outer metal 102, 104 as illustrated in FIGS. 10-11.

The final assembly as illustrated in FIGS. 17-20 is pushed into an outercan of a leaf spring assembly, such as illustrated in FIG. 5. Amechanical overlap is created between the first bushing assembly portion(or component) 102 a and the second bushing assembly (or component) 102b. A bolt 116 is inserted through the inner metals and tightened downwith a fastener. A portion of the vehicle's weight is then distributedacross the two bushings 100 a, 100 b. The bottleneck feature preventsthe assemblies from dislodging themselves during axial loading andprovides for improved performance characteristics as compared to theprior art.

It should be noted that the configuration discussed above may also bereversed. This configuration is illustrated in FIG. 1B at the assembly101. The configuration of the assembly 101 connects the wider ends 120,121 instead of the tapered portions. The assembly can be applied tobusing with through holes for bolts (such as shown in FIG. 1A) or barpins which do not extend through the center of the part. Further, theassembly may connect without a fastener by means of overlapping,adhesives, welding or other known connection means.

It is noted that the terms “substantially” and “about” may be utilizedherein to represent the inherent degree of uncertainty that may beattributed to any quantitative comparison, value, measurement, or otherrepresentation. These terms are also utilized herein to represent thedegree by which a quantitative representation may vary from a statedreference without resulting in a change in the basic function of thesubject matter at issue.

While particular embodiments have been illustrated and described herein,it should be understood that various other changes and modifications maybe made without departing from the spirit and scope of the claimedsubject matter. Moreover, although various aspects of the claimedsubject matter have been described herein, such aspects need not beutilized in combination. It is therefore intended that the appendedclaims cover all such changes and modifications that are within thescope of the claimed subject matter.

1. A bushing comprising: an outer rigid portion and an inner rigidportion concentrically arranged around each other, the inner rigidportion being the innermost component; a flexible portion positionedbetween the inner rigid portion and the outer rigid portion, theflexible portion configured to space apart the outer rigid portion andthe inner rigid portion; and each of the outer rigid portion, the innerrigid portion and the flexible portion having a tapered end configuredto connect with a fastener.
 2. The bushing of claim 1 wherein theflexible portion is bonded rubber, the bonded rubber bonded to at leastone of the outer rigid portion or the inner rigid portion.
 3. Thebushing of claim 2 wherein the bonded rubber of the flexible portionincludes a textured outer surface, the textured outer surface positionedadjacent to an inner surface of the outer rigid component.
 4. Thebushing of claim 2 wherein an outer surface of the flexible portionincludes a plurality of ridges, the plurality of ridges positionedadjacent to an inner surface of the outer rigid component.
 5. Thebushing of claim 1 wherein the outer metal portion includes a maincylindrical section extending to tapered end.
 6. The bushing of claim 1wherein the rigid inner portion and the rigid outer portion are madefrom a material selected from the following: metal, plastic and/orpolymer.
 7. The bushing of claim 1 wherein the flexible portion is arubber, the outer rigid portion is metal and the inner rigid portion ismetal, the rubber of the flexible portion is bonded to at least one ofthe outer rigid portion and the inner rigid portion.
 8. The bushing ofclaim 1 wherein the outer rigid portion is concentrically arrangedaround the flexible portion, the flexible portion is concentricallyarranged around the inner rigid portion wherein each of the outer rigidportion, the flexible portion and the inner rigid portion include acentral bore, the inner rigid portion configured to receive thefastener.
 9. A bushing assembly comprising: a first component having afirst outer metal portion, a first inner metal portion and a firstrubber portion concentrically arranged around each other, the firstrubber portion spacing apart the first outer metal portion from thefirst inner metal portion, at least one of the first outer metalportion, the first inner metal portion and the first rubber portionhaving a first tapered end; a second component having a second outermetal portion, a second inner metal portion and a second rubber portionconcentrically arranged around each other, the second rubber portionspacing apart the second outer metal portion from the second inner metalportion, at least one of the second outer metal portion, the secondinner metal portion and the second rubber portion having a secondtapered end; and a fastener configured to connect the first tapered endof the first component and the second tapered end of the secondcomponent, the first component and the second component configured to atleast partially overlap; wherein the bushing assembly forms a bottleneckshaped center portion when fully assembled.
 10. The bushing assembly ofclaim 9 wherein the first and second outer metal portions areconcentrically arranged around the respective first and second rubberportions.
 11. The bushing assembly of claim 9 wherein the first andsecond rubber portions are concentrically arranged around the respectivefirst and second inner metal portion.
 12. The bushing assembly of claim9 wherein the first and second inner metal portions are configured toreceive the fastener.
 13. The bushing of claim 9 wherein a rubber of thefirst rubber portion is bonded to at least one of the first outer metalportion or the first inner metal portion.
 14. The bushing of claim 9wherein a rubber of the second rubber portion is bonded to at least oneof the second outer metal portion or the second inner metal portion. 15.The bushing of claim 12 wherein the bonded rubber of the rubber portionincludes a textured outer surface, the textured outer surface positionedadjacent to an inner surface of the outer metal component.
 16. Thebushing of claim 12 wherein an outer surface of the rubber portionincludes a plurality of ridges, the plurality of ridges positionedadjacent to an inner surface of the outer metal component.
 17. Thebushing of claim 9 wherein the outer metal portion includes a maincylindrical section extending to tapered end.
 18. A leaf spring assemblycomprising: a leaf spring having an eye positioned at a free end, theeye configured to hold a bushing; the bushing having: a first componenthaving a first outer metal portion, a first inner metal portion and afirst rubber portion concentrically arranged around each other, thefirst rubber portion spacing apart the first outer metal portion fromthe first inner metal portion, at least one of the first outer metalportion, the first inner metal portion and the first rubber portionhaving a first tapered end; a second component having a second outermetal portion, a second inner metal portion and a second rubber portionconcentrically arranged around each other, the second rubber portionspacing apart the second outer metal portion from the second inner metalportion, at least one of the second outer metal portion, the secondinner metal portion and the second rubber portion having a secondtapered end; and a fastener configured to connect the first tapered endof the first component and the second tapered end of the secondcomponent, the first component and the second component configured to atleast partially overlap wherein the bushing assembly forms a bottleneckshaped center portion when fully assembled
 19. The leaf spring assemblyof claim 18 wherein the first and second outer metal portions areconcentrically arranged around the respective first and second rubberportions.
 20. The leaf spring assembly of claim 18 wherein the first andsecond rubber portions are concentrically arranged around the respectivefirst and second inner metal portion.